Tuner for high-frequency tubes



Dec. 23, 1952 F. A. JENKS 2,623,194

TUNER FOR HIGH-FREQUENCY TUBES Filed April 3. 1947 26' 29 i. I 25 27 h 'l F% a 28 19 f4 ff /7 a 9 6 A9 &

ATTORNEY Patented Dec. 23, 1952 UNITED smr as wear TUNER FOR HIGH-FREQUENCY TUBES Frederic A; Janka: Dcdham; i Mass, assignor to" The Sperry Corporation; aicorporation of Dela-- ware lipplicati on April k 1947,,Serial No; 739,2'1L

8 Claim 1.

This inventionrelates, generally, to tuners forhighirequency tubes; and the invention 'has ref erencej more: particularly, to a novel: tuner for high frequency-tubes employing cavity/resonatorssuch as the kiystron tube;

High frequency; tubes of the klystron typeem ploy. cavity: resonators which have-to be tunedto 1 the desired operating: frequency of I the tube;

Wherethe tube contains 'more-tha-n one cavity resonatonit isiusuallyenecessary-to tune'each cavlty so that its operating frequency will equal that or be a harmonic of the frequency of theothercavity resonatoror resonators :thereofz Heret0fore-,-where tubes employ a--plurality. of

cavity resonators, it-has been difficultto provide simple anddependable means fortuning'two or more cavities simultaneously while maintaining the desired fixed frequencyl relationship between thesecav iti'esi Thus; in the prior art conductive 2O rod'ftuners" have been introduced into regions of intense electric field or intense" magnetic field components of an excited cavityreson'ator'; there:

bycausing alteration of the' equivalent'capacitaii'ce' or "of theequivalent'induetance of theresonatoi'-," but it hasbeen difiic'ult" to effect simii tan-eons equivalent-insertion 1 of theserods i plurality of" resonators at one time and" in amounts ne'eessaryrto obtain aecurategangturi-=- rality of resonators, difficulty li-as beeri encount ered -in' the -rod acting as th' c'onductor of a ccncentric line therebyurid resoriatoi'sto'getherwitri-th takes plae p'rodi'iciiig undesired oscillationsi Tlie pririoipal Obj c-t Of' tHe present invention iS -t'c '"-provice iioii l tl'lilei adaptedftd gafi'g tilfii' a-pmrauty' or? cavity 'resonators simultaneously} said 'tiin'er beingso -const'riiliated" and arranged h as to enable exact trackih'g"of thefoperating'fi'e quencies of the several cavitieswhilat the same timepre'ventin'gundesired feedback'between the cavities.

Another ob'ject of the"present 'invention isto provide R HOVEI gaiili'g tlifiei em loying a dielectric rod" having conducting tuning elements thereon andextending through aligned bores in-the walls" of cavity resonators; saidrod andbores -beir'i'g'SQ proportioned 'asto act as awavegiiide below-cut ofi, thereby reducing coupling-between the res-"-' onators to aminimum'and hence preventing' en countered feedback and 1 undesired oscillations.

It isanotlier ob'ject'of-"tliepresentinventioi1 pro'vice never tuner" marine" for" com=- 2 pen'satifig for temperature changes while at the same time providingan exceedingly sensitive control-of the: frequency;

Another object of-the present invention is to. provide-a noveltuner'whichiis adapted to'operatelargely; in the magnetic portion ofv the resonator field oriwhich may 'operate in thatr'egion' of the resonator occupied b'yxboth magnetic and electric field. components, thereby. enhancing the tuningrange of: the tube.

The inven'tionlalso' relates to the: novel features;

of the instrumentalities described herein, whether ornot such arc used for'the stated objects; or'in the stated 3 fields or combinations.

Other objects of the-invention will become apparent from the following description taken in connection with the accompanying drawings wherein:

Fig. Lisa longitudinal, part-sectional view of an ultra-high-frequency tube of the klystron type equipped withthe novel tuner of this invention;

Fig. 2 is a sectional view taken along .1mes=2-'-2:

of Fig. 1 looking in the direction of'the arrows;

Fig. Bis an enlarged sectional View of'a portion oi the structur-e" of "Fig; 1-; I and Fig: 4 -is 'a-se'ctional fragmentary view of a mod ified structure.-

Rieferr-ing now 'to Fi'gs'. 1-3=of the drawings; the reference-numeral l designates an ultra'-high'-' frequency tubeof the klystrontype, having-Ia fecii'ssing emitter assembly 2 adapted to formin oenjunctionwith an accelerating battery (not show-n): a stream of electrons passing central-1y througlia serie's oi ca vity resonators, 3-; 4i and 5 provided viiitliin -the casing of the tube; Output and input power'connections to "thecavity resonato' field f'ree drift sp'aces iiand 1 0 are provided/between the resonators 3 and-4 and 4 and Sec that velocity modulationtaking plaee in 'the resonators is 'converted i'ii-te dehsity' modulation in the i drift spaces. The resonators 3; 4 and- 5 are sho'wii 'p'rc vided with-conductive cylindrical walls! I, ll Z-and- IS preterabl-yof massive metal construction to enabiethe TabiddiSSipatMri O-f h'e'atl 1 According to" the referred arrangement,: the walls l'l' 'j I2- and l'3 of thetube casing are pro vide'd With axially aligned bies 01 giiids M [5. and It located 5 ecceritrically' with "respect- 130 able; The bores I 4; [5 and [E and therod i! are so proportioned as to act a 's a wave g'uiile below c-iit-ofi at the operating frequencies" of the of the tub'e are provided by: use of con centric liii'e ter'mi-nals 6i i and B; Substantially tlie drif t spaces 9' ai1d I El -and within which-a di'electrie' rocl Ii -as of quartzor glass islongitudihally niew' 3 resonators 3, 4 and 5, thereby reducing the coupling between these resonators by way of the bores and dielectric rod to a minimum, and preventing undesired feedback between the resonators.

In order to efiect the tuning of the resonators, the dielectric rod I1 is provided with mutually spaced conducting sleeves or slugs l8, l9 and 20. These sleeves may be electro-deposited copper, for example, although any conducting material such as silver may be used. The sleeves l8, l9 and are so positioned on the rod II that as this rod is moved they enter the respective cavity resonators simultaneously and progress into these resonators by equal amounts as the rod I1 is moved.

Inasmuch as the rod l"! is a unitary structure, any movement of this rod effects equal movements of the sleeves l8, l9 and 20 resulting in accurate tuning of the resonators and accurate tracking of all the resonator frequencies. To effect movement of the rod II, the same is provided with a thin projecting stem 22 as of tungsten which projects into a sleeve 23 and is secured to the sleeve at its outer end portion 24. The sleeve 23 is, in turn, fixed at its inner end to a cylindrical cup-shaped member 25 having an outer flange portion 26 sealed to one end of a bellows 21, the other end of which bellows is sealed to a cylindrical sleeve member 28 forming a part of the high frequency tube housing, said sleeve member 28 surrounding the rod ll.

Thus, the member 25 in conjunction with bellows 21 and sleeve 28 form a sealed joint permitting longitudinal movement of the rod l1 without affecting the vacuum within the tube. A cover member 29 is attached to the sleeve 23 and carries a bushing 30 within which is turnably mounted hollow shaft 31 provided with suitable flanges for preventing longitudinal movement thereof while permitting turning movement of the shaft.

The outer end of the shaft 31 has a knob 32 secured thereon as by the set screws 33. The hollow shaft 3| surrounds the stem 22 and sleeve 23. This shaft has its inner end threaded at 34 for cooperating with a nut 35 fixed within the cup-shaped member 25. Thus, by turning knob 32, shaft 3| is also turned within the bearing 30 and threaded portion 34 cooperating with nut 35 serves to move the cup-shaped member 25 and hence sleeve 23 longitudinally. Since this sleeve is attached to stem 22, the rod II also moves. The sleeve 23 is made of a material such as copper having a coefficient of thermal expansion different from that of the stem 22 so that this bimetallic structure automatically compensates for expansion and contraction of the resonator walls due to operating temperature changes, thereby enhancing the accuracy of the tuning and preventing drifting of the tuned frequencies.

In the form of the invention shown in Fig. 4, the tuning mechanism is shown for tuning resonators operating at different frequencies. Thus, the resonator 36 will operate at a fundamental frequency while the output resonator 31 operates at a higher harmonic thereof. The dielectric rod l'! in this instance is reduced at 38 where it projects into the harmonic resonator 31. The conducting sleeve 39 on this portion of the rod is also of reduced diameter. The operation of the apparatus shown in Fig. 4 is similar to that of the previous figures and feedback is prevented in the same manner.

Inasmuch as all the tuning sleevesmove simultaneously and to the same extent, accurate tracking of the frequencies of the resonators takes place where a plurality of resonators is used. Owing to the use of the stem 22 and sleeve 23 of different thermal expansion coeflicients, drifting of the resonator frequencies due to temperature changes is largely avoided.

Since many changes could be made in the above construction and many widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a high frequency tube structure having a casing providing a plurality of cavity resonators therewithin, each of said resonators adapted to contain an independent oscillating electromagnetic field, tuning means therefor comprising, a dielectric rod slidable within a bore in said casing interconnecting said resonators, said rod and bore being of a diameter less than that sufficient to guide energy at the resonant frequency of said cavity resonators, mutually spaced tuning sleeves carried by said rod, and means for actuating said rod whereby the same is moved to effect movement of said tuning sleeves into and out of the respective resonators to effect the gang tuning by altering the electromagnetic field in each of said resonators.

2. In a high frequency tube structure of the character described in claim 1 wherein said rod actuating means comprises an actuating knob, screw and nut means actuated thereby, and thermal compensating means interconnecting said screw and nut means to said dielectric rod for effecting movement of the latter while compensating for thermal expansion and contraction of the tube casing.

3. A high frequency tube structure comprising a casing, a plurality of cavity resonators contained within said casing, each of said resonators adapted to contain an independent, oscillating electromagnetic field said casing having a bore interconnecting said resonators, and a dielectric rod slidable within said bore, said rod having conducting members thereon for effecting gang tuning by altering the electromagnetic field in each of said resonators.

4. Ultra high frequency apparatus comprising a plurality of hollow cavity resonators, each of said resonators adapted to contain an independent, oscillating electromagnetic field, means for altering the electromagnetic field in each of said resonators, said means comprising a dielectric rod mounted for translational movement within said resonators, and respective conducting members carried by said rod for movement into and out of said resonators.

5. Ultra high frequency apparatus as defined in claim 4, comprising manually operable means for moving said rod, said manually operable means including a bimetallic element for compensating for temperature changes of the resonator.

6. A high frequency tube structure comprising a casing, a plurality of cavity resonators contained within said casing, said resonators operating at differing frequencies and having differing proportions, said casing having a bore interconnecting said resonators, a dielectric rod slidable within sald bore for effecting simultaneous tuning of said resonators, said rod having conducting members thereon for entering the fields of said resonators, the proportions of the conducting members carried by said rod varying in accordance with the relative proportions of the respective resonators.

'7. A high frequency tube having a casing formed with a plurality of cavity resonators therein and having a tuning bore interconnecting said cavity resonators, tuning means for said tube comprising, a dielectric rod projecting through said bore into said cavities from without said casing, means sealing the joint externally of said casing between said rod and said bore, and external means connected with said rod for actuating said rod from a point externally of said sealing means.

8. An ultra high frequency tube having a cathode, an anode, a plurality of cavity resonators oriented along a common axis between said cathode and anode, each of said cavity resonators being adapted to contain an independent, oscillating electromagnetic field, a plurality of tuning bores in the walls of said resonators, said tuning bores being positioned along a common axis, said axis being arranged parallel to the axis of said resonators and spaced thereform, a dielectric rod slidably mounted within said bores, conducting members supported by said rod, and means for longitudinally displacing said rod. FREDERIC A. JENKS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

